Antiperspirant compositions have become a part of many persons' personal care and grooming regimen. The antiperspirant active materials which have been typically used include astringent metallic (e.g., aluminum, zinc, and zirconium) salts such as salts of aluminum halides, aluminum hydroxyhalides, zirconyl oxyhalides, zirconyl hydroxyhalides, and complexes of aluminum, zirconium and amino acid (e.g., glycines). These materials, naturally, are sensitive to the presence of water and are preferably stored and delivered to the skin in the substantial absence of water in order to preserve efficacy. Additionally, it is generally perceived as unpleasant for the antiperspirant composition to have a "wet" feel upon application to the skin. Hence, it is also desirable to deliver the antiperspirant active to the skin by a vehicle which minimizes this feeling of wetness. The delivery vehicle must also not cause excessive staining of the user's clothing, and should control or reduce chalky appearance on the skin (and potential rub-off onto the user's clothes) resulting from the antiperspirant active, suspension agent, or other material in the composition. For these reasons, a variety of volatile silicones and non-volatile silicone emollients, and combinations thereof, have commonly been utilized in liquid antiperspirant compositions for delivery of the antiperspirant active material.
The primary silicone material used in recent times for delivery of antiperspirant actives in roll-on liquid antiperspirant applications is volatile cyclomethicone. Volatile cyclomethicone provides a very dry feel upon application and has a low heat of evaporation. The low viscosity of the volatile fluids is also important for providing an easily flowable composition for roll-on or aerosol application. In many of these compositions, a relatively low level of certain non-volatile silicone fluids, or other non-volatile emollient such as paraffin oil (e.g., mineral oil) is also included. These non-volatile fluids generally have a high enough viscosity so that they remain deposited on the skin throughout a significant portion of the day. They also inhibit occurrence of, and consequently rub-off of, chalk-like residue formed from the antiperspirant composition's particulate ingredients. These non-volatile materials are typically utilized at relatively low levels (about 1% to about 12%) to minimize an undesirable "greasy" feel which they can impart.
Liquid roll-on antiperspirant compositions such as these are exemplified in numerous publications including U.S. Pat. No. 4,863,721, Beck et al., issued Sep. 5, 1989. European Patent Application Publication No. 330,140, published Aug. 30, 1989, and U.S. Pat. No. 4,423,041, Clum et al., issued Dec. 27, 1983.
Other liquid emollients have also been used in liquid antiperspirant compositions. These include paraffins such as mineral oil, and a variety of alcohols and esters of alcohols and fatty acids. However, these emollients also have draw-backs which, typically, include skin irritation and greasy feel.
Whereas liquid antiperspirant compositions containing high levels of volatile silicone have provided consumer-acceptable performance and have generally attained a following in the marketplace, the use of such antiperspirant compositions can produce skin irritation in the form of itching, redness, rash, and/or burning (alternately referred to as "stinging"), particularly when applied immediately or soon after shaving. Although the incidence of this is not experienced for all application usages or by all people, it would nevertheless be desirable to provide a liquid antiperspirant composition that could be used for roll-on applications which provide reduced incidence of skin irritation while still providing excellent cosmetic properties, e.g., low "wetness", low levels of "chalky" residue, and low levels of rub-off onto clothing. It would also be desirable to provide liquid antiperspirant compositions useful for aerosol application that have reduced incidence of in-use skin irritation and which retain excellent cosmetic properties. It is an object of this invention to provide such liquid antiperspirant compositions useful for both roll-on and aerosol applications.